Cured polyferrocenylenes and process for curing

ABSTRACT

CURED POLYFERROCENYLENES AND THE PROCESS FOR CURING THEM ARE DISCLOSED. LOW MOLECULAR WEIGHT THERMOPLASTIC POLYFERROCENYLENES ARE REACTED WITH AROMATIC DICARBOXALDEHYDES. THE RESULTING COPOLYMERS CROSS-LINK AND CURE TO HARD, HEAT-RESISTANT, RADIATION-RESISTANT STRUCTURES UPON TREATMENT WITH HEAT AND PRESSURE.

United States Patent 3,640,959 CURED POLYFERROCENYLENES AND PROCESS FORCURING Norman Bilow, Los Angeles, Calif., and Harold Rosenberg, Dayton,Ohio, assignors to the United States of America as represented by theSecretary of the Air Force No Drawing. Filed Mar. 6, 1969, Ser. No.805,008 Int. Cl. C08g 3/00, 13/00 U.S. Cl. 260-64 11 Claims ABSTRACT OFTHE DISCLOSURE Cured polyferrocenylenes and the process for curing themare disclosed. Low molecular weight thermoplastic polyferrocenylenes arereacted with aromatic dicarboxaldehydes. The resulting copolymerscross-link and cure to hard, heat-resistant, radiation-resistantstructures upon treatment with heat and pressure.

BACKGROUND OF THE INVENTION (1) Field of the invention This inventionrelates to the process of reacting thermoplastic polyferrocenylenes withvarious aromatic dicarboxaldehydes in the presence of a suitablecatalyst and thus producing new copolymers which are thermosetting.

(2) Description of the prior art In the prior art, methods ofsynthesizing polyferrocenylenes have been described by variousinvestigators. The polyferrocenylenes produced by the prior art have allhad one property in common. They have all been thermoplastic orcompletely intractable and insoluble. Therefore, up to the present time,it has been impossible to take full advantage of the heat and radiationresistance or ablative properties potentially offered by the ferrocenemoiety, especially in the field of reinforced composite structures.

SUMMARY OF THE INVENTION This invention discloses a method for curingpolyferrocenylenes and thus makes it possible to take full advantage ofthe heat and radiation resistance, as well as ablative and insulativeproperties, heretofore only potentially offered by the ferrocene moiety.In practicing the invention, one may utilize the lower molecular weight,organic-soluble fraction of polyferrocenylenes obtained from a varietyof prior art methods. The said lower molecular weight portion may beisolated and treated with various dicarboxaldehyde curing agentsdescribed herein. Treatment of the polyferrocenylenes with the disclosedcuring agents produces new copolymers. The. copolymers produced arethermosetting, moldable and useful in the formation of laminates andfilled composite structures where high heat resistance and radiationresistance are desirable properties.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In practicing this invention,typical polyferrocenylenes of the following types may be utilized:

0 ll o w Fe Fe Fe Type I Type II Type III where n is an integer of about2 to 15. Ring hydrogens of either or both of the polyferrocenylene ringsmay be replaced by another suitable radical. Among those that aresuitable are radicals selected from the group consisting Of CH3, C2H5,C3H7, C4H9, C5H11, Cal I5, C1, F, z a 2 2 5, s a z, CHaO, 2 5 and CH S.

Curing agents useful in the process are: terephthalaldehyde,isophthalaldehyde, 1,1'-ferrocenedicarboxaldehyde, 4,4biphenyldicarboxaldehyde, 3,4 biphenyldicarboxaldehyde, 3,3biphenyldicarboxaldehyde, and dicarboxaldehydes of the type wherein thealdehyde groups are 3,3; 3,4; or 4,4 and Z is 0, CH C H S0 C H S orvarious other connecting moieties such as other alkylene or arylenemoieties.

Preferred catalysts are boron trifluoride, aluminum trichloride, zincchloride or stannic chloride, with the former the most preferred.

The reaction may be generally illustrated as follows:

@CHZ cno BF Fe cno wherein n is an integer of from 2 to 10. The letter mis to indicate an integer which varies from about 2 to 20 and refers tothe number of repeating units of a partially cured polymer which issuitable for molding purposes as compared to a very high, undeterminedinteger for the number of repeating units of the polymer in the form ofa completely cured product which has been subjected to the heat andpressure of the molding process. The completely cured products areestimated to have molecular weights of over thousand.

The following are more specific examples to better illustrate theinvention. It should be recognized that any of the starting compoundsand catalysts disclosed above could be utilized.

EXAMPLE I Polyferrocenylene of Type I above (3.5 grams, 0.0026 mol) andanalyzed to have a molecular weight of 1365 (analysis by vapor phaseosmometry) and terephthaldehyde (1.2 grams, 0.009 mole) were dissolvedin 20 ml. of anhydrous ether as completely as possible. Borontrifluoride etherate (0.1 gram, 0.0007 mole) was then added to thesolution. The ether Was removed by evaporation and the solid mixtureground to a fine powder. The powder was melted at C. and reacted in itsmolten state for 11 minutes. After cooling, the partially cured productwas found to be a polymer which melted at 60- 90 C. It cured to a hardresin at C.

4. stacked in a mold and cured for approximately one hour at 288 C. and2500 p.s.i. The result was a laminate with very good properties.

EXAMPLE III Other typical examples of the fabrication ofterephthalaldehyde-cured polyferrocenylene laminates aretabulated in theaccompanying table. These examples utilized Type I polyferroceneylenesin the 1100 to 4000 mean molecuthen be removed by vacuum evaporation orby air drying 10 lar weight range.

COMPOSITION AND FABRICATION PARAMETERS ON VARIOUSTEREPHTHALALDEHYDE-CURED POLYFERROCENYL- ENE LAMINATES Catalyst, MoldingSamplo Polyferroeenylene Curing agent BF -etherate Advancing temper-Moldlng Reln- Resin size Lacquer tcmpera- Time, ature, pressure,forcecontent, diam- Sample Grams Moles M3 Grams Moles Grams Molessolvent 0. hours C. p.s.i. ment percent eter 6. 0. 0015 4, 000 0. 7 0.005 0. 20 0. 0014 CHzClz 40 0.50 288 2, 500 C CA-l 100 3. 0. 0026 1,365 1. 2 0. 009 0. 0. 0007 CHzClz 140 0. 288 2, 000 C glA- 9. 0 0. 00701, 290 3. 0 0. 024 0.60 0.0035 CHzClz 200-315 4, 000 181- E 36 0. 01901, 880 12. 0 0. 089 1. 00 0. 0070 CHzClz 315 2, 000 C (13A- 30 2" 48 0.0260 1, 880 16. 0 0. 120 1. 30 0.0091 CHzClz 315 2, 000 (15A- 2 20 0.0100 2, 020 4. 0 0. 030 0. 0.0018 CHzClz 315 750 lSI E 20 0. 0100 2, 0204.0 0.030 0. 25 0.0018 CHzClz 315 1, 000 181-E 18 0. 0090 2, 020 6.0 0.045 0.63 0. 0044 CH2C12 315 l, 000 181-E 18. 5 0. 0160 1, 100 6. 0 0.045 0. 63 0. 0044 CHzClz 343 l, 000 181-1?- and the dried coated fabriccut into plies, stacked, and molded under heat and pressure. This methodis more effective where the reactant polymer has a molecular weight offrom 1000 to about 4000.

(2) A second method is to melt suitable amounts of polyferrocenylene,curing agent and catalyst together in the absence of a solvent andreacting the materials until viscosity is suitable for folding orlaminating. In this manner a partial cure is effected. When the properviscosity has been obtained, reinforcing material may be coated, placedin a mold and subjected to heat and pressure. This method was used in afew cases where the reactant polymer had a molecular weight of less than1000.

(3) A third method is to dissolve the still low molecular weight,partially cured, viscous polymer of method (2) in a suitable lacquer orvarnish type solvent and then proceed with the coating in the mannerdisclosed by method 1 All three methods give laminates with excellentproperties.

Lacquer or varnish type solvents found useful in methods (1) and (3)include methylene chloride, chloroform, carbon tetrachloride,tetrachloroethylene, acetone, and methylethyl ketone. Suitablereinforcing materials include carbon cloth, glass fabric, quartz cloth,asbestos fibers and the like. Any reinforcement known in the art wouldbe suitable.

, Temperatures used in the molding process ranged from about 200 C. toabout 350 C., and pressures used varied from 750 p.s.i. to about 4000p.s.i. Molding times were in the range of from minutes to about 2 hours.Generally about one hour of molding was suflicient to give an excellentlaminated product. 1

EXAMPLE II Polyferrocenylene of Type I above (6.0 grams, 0.0015 mole)having a molecular weight of 4000 and terephthalaldehyde (0.7 gram,0.005 mole) was dissolved in 20 m1. of methylene chloride and borontrifluoride etherate (0.2 gram, 0.0014 mole) was added. The solution waswarmed at C. for 30 minutes. The lacquer thus formed was applied as acoat to carbon cloth and dried. The coated carbon cloth was then cutinto p es. T plies were Not only are these polymers useful as matrixresins for structural laminates and fabric reinforced ablative andinsulative composites, but they are also useful in fabricating filledresinous compositions wherein fillers such as various clays, silica,powdered glass, mica, minerals, pulverized thermoset phenol-formaldehyderesin, sodium aluminum silicate, and carbon are incorporated therein.

Fillers may be incorporated by grinding them together with the ferrocenepolymer prior to curing the polymer or by blending the filler with asolution of the uncured ferrocene polymer and subsequently removing theresin solvent by evaporation.

The list of useful fillers indicated above is presented to provideillustrative examples but is not intended to limit the scope of thisinvention. Filler content may be as low as 1% or less or as high as Forcertain fillers this upper limit is only 40-60% depending upon thedensity of the selected filler, Mixtures of fillers may also be used.

We claim:

1.- The copolymers consisting essentially of the general formula:

wherein n is an integer of from 2 to 10, wherein m is an integer of from2 to 20, wherein R and R are selected from the group consisting of H, CHC 11 C H 4 9 5 11, e s, c1, z s, z z s, C H CH CH O C H O, and CH S, andwherein X is selected from the group of diradicals consisting of C HC6H4C5H4, C H FeC I-I and C5H4-Z-CgH4 in Z is selected from the groupconsisting of O, S, CH C H S0 and C H 5 2. The copolymers consistingessentially of the general formula:

c li I I Fe O X 6% I:

R' n D m wherein n is an integer of from 2 to 10, wherein m is aninteger of from 2 to 20, wherein R and R are selected from the groupconsisting of H, CH C H C3H7, C H 5 11, e s z a 2 2 s, s s z, CHgO, C HO, and CH S, and wherein X is selected from the group of diradicalsconsisting of C H C H C H C H FeC H and C H Z-C H in which Z is selectedfrom the group consisting of 0, S, CH C H S02 and C6H4.

3. The copolymers consisting essentially of the general formula: qr

wherein n is an integer of from 2 to 10, wherein m is an integer of from2 to 20, wherein R and R are selected from the group consisting of H, CHC H C H- 4 9, 5 11 e s C1, R Br, 2 3, 2 2 5, C H CH CH O, C H O, and CHS, and wherein X is selected from the group of diradicals consisting ofC H C6H4C5H4, C5H4FGC5H4 and C6H4ZC6H4, ill which Z is selected from thegroup consisting of O, S, CH C H S02 and C5H4.

4. The process of forming copolymers of polyferrocenylenes anddicarboxaldehydes which comprises reacting a polyferrocenylene selectedfrom the group consisting of wherein the aldehyde groups are located inthe 3,3; 3,4; or 4,4 positions and wherein Z is selected from the groupconsisting of O, S, CH C H S0 and 0 H, m

7 the presence of a catalyst selected from the group consisting of borontrifiuoride etherate, boron trifluoride, aluminum trichloride, zincchloride and stannic chloride said reaction being conducted in thepresence of a solvent selected from the group consisting of methylenechloride, chloroform, carbon tetrachloride, tetrachloroethylene, acetoneand methyl ethyl acetone which is inert to the reactants.

5. A process according to claim 4 wherein said copolymer is recovered byremoving said solvent.

6. A process according to claim 5 wherein said copolymer is cured byheating under pressure.

7. A process according to claim 6 wherein a filler is mixed with saidcopolymer prior to curing by heating under pressure.

8. The cured copolymer produced by the process of claim 6.

9. The filled, cured copolymer produced by the process of claim 7.

10. The process of forming copolymers of polyferrocenylenes anddicarboxaldehydes which comprises:

(a) mixing a compound selected from the group consisting of wherein n isan integer of from 2 to 10 and R and R are selected from the groupconsisting of H, CH Z S! C3H'I: 4 9 s n, s s, C1, z s CO2C2H5, C6H5CH2,CH30, C H O, and a dicarboxaldehyde selected from the group consistingof terephthalaldehyde, isophthalaldehyde, 4,4- biphenyldicarboxaldehyde,3,4 biphenyldicarboxaldehyde, 3,3 biphenyldicarboxaldehyde,1,1-ferrocenedicarboxaldehyde, and dicarboxaldehydes of the type havingthe formula R 1 9 @Anr @c c RI n n n Ol-IC CHO References Cited UNITEDSTATES PATENTS 3,437,634 4/ 1969 Neuse 260-47 3,437,644 4/1969 Neuse eta1. 260- 3,448,082 6/1969 McGrath et a1 260-67 3,504,052 3/1970 Neuse eta1. 260-86 WILLIAM H. SHORT, Primary Examiner L. L. LEE, AssistantExaminer US. Cl. X.R.

117l24 E, 161 L; 161198; 26032.8 R, 33.8 R, 67 R

